SCRREEN
Coordination and Support Action (CSA)
This project has received funding from the European Union's Horizon 2020 research and innovation programme
under grant agreement No 730227. Start date : 2016-12-01 Duration : 30 Months
www.scrreen.eu
Circular Economy and zero waste aspects and business models of production
Authors : Mrs. Marjaana KARHU (VTT), Joanna Kotnis, Yongxiang Yang (TU Delft); Pierre Menger, Ainara Garcia Uriarte (Tecnalia); Kimmo Kaunisto, Elina Huttunen-Saarivirta, Elina Yli-Rantala, Marjaana Karhu (VTT); Lena Sundqvist Ökvist, Xianfeng Hu (Swerea MEFOS); Teodora Retegan (Chalmers); María González-Moya (IDENER); Michalis Samouhos, Maria Taxiarchou (NTUA); Michal Drzazga, Jolanta Niedbala (IMN) Ref. Ares(2018)2940216 - 05/06/2018
SCRREEN - D4.3 - Issued on 2018-06-05 11:46:50 by VTT
SCRREEN - Contract Number: 730227
Solutions for CRitical Raw materials - a European Expert Network Dimitrios Biliouris
Document title Circular Economy and zero waste aspects and business models of production
Author(s)
Mrs. Marjaana KARHU, Joanna Kotnis, Yongxiang Yang (TU Delft); Pierre Menger, Ainara Garcia Uriarte (Tecnalia); Kimmo Kaunisto, Elina Huttunen-Saarivirta, Elina Yli-Rantala, Marjaana Karhu (VTT); Lena Sundqvist Ökvist, Xianfeng Hu (Swerea MEFOS); Teodora Retegan (Chalmers); María González-Moya (IDENER); Michalis Samouhos, Maria Taxiarchou (NTUA); Michal Drzazga, Jolanta Niedbala (IMN)
Number of pages 206
Document type Deliverable
Work Package WP4
Document number D4.3
Issued by VTT
Date of completion 2018-06-05 11:46:50 Dissemination level Public
Summary
This deliverable reports the survey done in SCRREEN project in Task 4.3 relating to environmental trends and Circular Economy (CE) aspects of CRM production. For each CRM, the Circular Economy aspects were addressed in order to identify the gaps that limit performance of the processing chains, hinder closing the loop and hinder a zero-waste CRM production. Information on processes, production, solutions and eco-design principles for closing the loop of raw materials in order to support the zero-waste point-of-view, resource efficiency and energy efficiency simultaneously were gathered. In addition, the aspects supporting Circular Economy were evaluated trying to resolve the identified challenges. Lastly, the environmental issues e.g. toxicity related to CRMs production were reviewed.
Approval
Date By
D4.3 Circular Economy and zero waste
aspects and business models of production
Contributors:
Joanna Kotnis, Yongxiang Yang (TU Delft): Antimony, Indium, Dysprosium, Neodymium,
Praseodymium
Pierre Menger, Ainara Garcia Uriarte (Tecnalia): Beryllium, Borates
Kimmo Kaunisto (VTT): Magnesium
Elina Huttunen-Saarivirta (VTT): Cobalt, Tungsten
Elina Yli-Rantala (VTT): PGMs, Natural rubber
Marjaana Karhu (VTT): Phosphate Rock, White Phosphorus
Lena Sundqvist Ökvist, Xianfeng Hu (Swerea MEFOS): Coking coal, Natural Graphite,
Vanadium
Teodora Retegan (Chalmers): Bismuth, Fluorspar, Gallium, Helium, Tantalum
María González-Moya (IDENER): Germanium, Niobium
1
INTRODUCTION
European Commission recently published report on Critical Raw Materials and the Circular Economy1 suggesting
that the share of secondary sources in raw material supply is one of several simplified approaches to assess circular use of raw material. Despite the fact that several CRMs have a high technical and real economic recycling potential, the recycling input rate (a measure of the share of secondary sources in raw material supply) of CRMs is generally low. One reason for that is that sorting and recycling technologies for many CRMs are not available yet at competitive costs. In addition, the supply of many CRMs is currently locked up in long-life assets, which implies delays between manufacturing and scrapping and influences negatively to present recycling input rates. One reason is also that the demand for many CRMs is growing in various sectors and the contribution from recycling is largely insufficient to meet the demand.
This deliverable reports the survey done in SCRREEN project in Task 4.3 relating to environmental trends and Circular Economy (CE) aspects of CRM production. For each CRM, the Circular Economy aspects were addressed in order to identify the gaps that limit performance of the processing chains, hinder closing the loop and hinder a zero-waste CRM production. Information on processes, production, solutions and eco-design principles for closing the loop of raw materials in order to support the zero-waste point-of-view, resource efficiency and energy efficiency simultaneously were gathered. In addition, the aspects supporting Circular Economy were evaluated trying to resolve the identified challenges. Lastly, the environmental issues e.g. toxicity related to CRMs production were reviewed.
1 European Commission 2018. COMMISSION STAFF WORKING DOCUMENT. Report on Critical Raw Materials and the Circular Economy. Brussels, 2018. Available: https://ec.europa.eu/commission/publications/report-critical-raw-materials-and-circular-economy_en
2
CONTENT
1 INTRODUCTION ... 2 3 ANTIMONY ... 5 4 BARYTE ... 11 5 BERYLLIUM... 17 6 BISMUTH... 23 7 BORATES ... 25 8 COBALT ... 30 9 COKING COAL ... 38 10 FLUORSPAR ... 40 11 GALLIUM ... 44 12 GERMANIUM... 46 13 HAFNIUM ... 56 14 HELIUM ... 59 15 INDIUM ... 62 16 MAGNESIUM ... 70 17 NATURAL GRAPHITE ... 74 18 NATURAL RUBBER ... 76 19 NIOBIUM ... 84 20 PLATINUM-GROUP METALS (PGM) ... 9121 PHOSPHATE ROCK AND WHITE PHOSPHORUS ... 99
22 RARE EARTH ELEMENTS ... 108
24 ERBIUM ... 115
25 EUROPIUM ... 120
26 GADOLINIUM ... 126
27 OTHERS (HOLMIUM, LUTETIUM, YTTERBOIM, THULIUM ... 132
28 LANTHANUM ... 139
29 NEODYMIUM, PRASEODYMIUM, DYSPROSIUM ... 146
30 SAMARIUM ... 157 31 TERBIUM ... 165 32 YTTRIUM ... 171 33 SCANDIUM ... 178 34 SILICON METAL... 184 35 TANTALUM... 194 36 TUNGSTEN ... 196 37 VANADIUM ... 202
3
ANTIMONY
3.1
INTRODUCTION
Antimony is a soft, silver-grey metal, which is used to produce antimony trioxide (Sb2O3). Sb is important for
several sectors, namely chemical industry, electrical industry, metal and mineral industry. Its main applications are flame retardants and lead-acid batteries as hardener. It is also used in lead alloys, in plastics as catalysts and stabilisers and as decolourizing agent in glass for electronics. The EU is completely reliant on importing unwrought antimony to meet the demand on Sb2O3. Antimony in form of unwrought metal was assessed as
critical material first in 2011 and this result remains the same in further assessments (European Commission, 2017).
3.2
CIRCULAR ECONOMY ASPECTS
Improving the efficiency of metal production requires taking a circular perspective, thinking of the whole value chain. A fully closed system is not possible to obtain, due to physical limitations. There will always be losses in the system because of the thermodynamics laws, human error, imperfect technology and economics. Yet many improvements in the area of metal production can be implemented (UNEP, 2013). The aim is to close the metal loop as far as it is possible, which can be achieved by implementing different strategies. First, material production phase has inevitable impact on the supply of resources, environment, and waste generation. Product design can contribute significantly to a more circular system by implementing better durability, design for reuse or recycling principles. Use phase, reusing or recycling the material from scrap and end-of-life products are subsequent elements of a closed-loop supply chain (European Commission, 2011; M. A. Reuter et al., 2015).
3.2.1
DESIGN
In order to assure efficient material use according to circular economy principles, reduction of generated waste is required. One of ways to achieve that is to minimise necessity of recycling by implementing better product design. The objective is to use less resources and lower material complexity (Reuter et al., 2015). In order to improve functionality of products, increasing number of different elements are mixed together. This causes difficulties in separating materials after products’ end of life and therefore hinder possibility to close the metal production loop (UNEP, 2013). Antimony is mostly alloyed with lead and other elements and joined with different materials as fire resistance (European Commission, 2017).
The concept of design for recycling is a way to overcome those issues. It includes understanding of physics involved in material separation. Yet, the design for recycling is a complex challenge, since it has to provide the same functionality using less material or less complex combinations, which increase the cost of products. Presently it is not the preferable solution since the metal value is too low. The price for antimony reaches 9
dollars per kilogram, which is rather low comparing to other metals. The design should then focus on maximising resource recovery and efficiency of the process (UNEP, 2013).
Another concept found in the literature is design for sustainability. This approach looks into the best sustainability performance of a design, not only recyclability, but also energy efficiency and durability as aspects of a life cycle thinking. The life cycle assessment (LCA) analytical tool helps designers to find hotspots of the specific product, identify trade-offs between better performance and environmental footprint. This enable making a comparison for choosing the most optimal option (UNEP, 2013).
3.2.2
MANUFACTURING
No specific information was found on circular economy aspects of antimony during product manufacturing. There is however some research on new scrap generated during production of goods, which is also a source of antimony. In general, new scrap is usually high purity, has known properties and high value, its recycling is economically beneficial and can be easily accomplished (Graedel et al., 2011).
New scrap of antimony is generated by manufacturers of solders and Sb-alloys and also at plants using alloys for production of end-use items. The Sb-containing new scrap can be put back to the production system at the plant or transferred to external recyclers. It is estimated that in 2000 in US 2000 tons of antimony was produced from the new scrap only (Carlin, 2000).No information was found for the EU.
3.2.3
END OF LIFE RECYCLING
The main obstacle for recycling to take place is lack of economic incentives. Metal producers will only process scrap material when they can profit from that operation, otherwise the recovery would increase the overall production cost. Currently most of the recycling activities are undertaken together with large scale primary production of carrier metals (iron, copper, lead, nickel and others). For valuable and scarce metals, like antimony, the demand is too little to run a dedicated recovery plant, due to high investment costs (UNEP, 2013). Moreover, most of the recovery technologies are still in laboratory stage and upscaling them to be used in the industry is presently a serious obstacle (Dupont, Arnout, Tom, Koen, & Jones, 2016).
With increasing stocks of metals in many different products, their successful recovery depends strongly on the collection rate of products bearing them. The collection is usually a logistic challenge, but also depends on policy, which can differ from country to country. Consequently, the collection rates are hindered by lack of awareness or motivation among consumers on recycling possibilities. In the end, valuable secondary materials end up in municipal waste streams, especially small electronic devices, like batteries in case of antimony.
After the end of life, used products become a source of secondary materials, making the recycling a very important aspect of metal use in the future. One of the issues connected to recycling is the time after material will be available for recovery. The availability of secondary material depends on the lifetime of Sb-bearing products, in particular flame retardants, lead-acid batteries, lead alloys used in multiple applications and plastics.
Yet, recycling can secure only part of future demand, due to the delay in materials availability for recovery. Another aspect is the fact, that amount of metals used in production in the past was lower than it is now. Also, there are always metal losses during primary production, as well as from recycling (UNEP, 2013). Current end of life recycling rate for antimony reaches 28% and the material is obtained mostly from lead alloys found in scrap lead-acid batteries (European Commission, 2017).
Another issue hindering the recovery of antimony is high dispersion of this metal in final applications. This is the case especially with flame retardants and catalysts used in plastics (European Commission, 2017).
Incomplete material liberation from the scrap products is next issue causing the material loss. Complex products often cannot be efficiently separated into pure materials and therefore land in wrong stream of recyclates. This is caused also by randomness and psychical properties of each material. The degree of liberation determines the quality of secondary raw materials (UNEP, 2013).
It is known that improved recycling technologies can be much more economically feasible than primary production, mostly due to lower energy use. Therefore, recycling techniques substantially reduce environmental footprint of metal production (UNEP, 2013).
3.2.4
RESIDUES
Industrial processes generate substantial amounts of waste, which can be a source of valuable metals. Research has shown that there are technologies tested ion laboratory scale to recover antimony from residues, yet often those operations are not economically feasible. This could be overcome by implementing different metallurgical processes in order to recover higher number of elements at the same time (European Commission, 2017; UNEP, 2013). As an example, treating lead processing residues (anode slime) by chloridization leaching and controlled distillation can recover not only silver and gold, but after further processing also antimony, arsenic, copper and bismuth (Cao, Chen, Yuan, & Zheng, 2010). Residues from zinc primary production are potentially sources of valuable metals, like antimony but also silver, cobalt, germanium or indium (UNEP, 2013).
3.3
ENVIRONMENTAL ISSUES
3.3.1
PRODUCTION
Growing global demand for metals causes necessity for mining lower quality ores to meet the material needs. The overall decrease of ore grades leads to higher amounts of ground material to be extracted, higher energy use to process the material and consequently growth in greenhouse gases emissions, land disruption, higher pollution and water use. Primary production residues can pose a danger of releasing dangerous or even toxic substances to the soil or water, while being stored in ponds. Recycling of those production waste streams will
Primary and secondary production include multiple processes that are generating emissions to the atmosphere and thereby can cause environmental issues. Different production processes using furnaces with coal as a fuel can contribute to antimony emissions. Fly ash produced during the coal combustion process are carrying dangerous and often toxic elements and releasing them to the environment. The fly ash is a heterogeneous mixture of fine particles with varying composition, depending on the carbon used in the combustion. Sb is vaporised in the combustion process and constitutes the largest anthropogenic source of antimony released to the atmosphere, which can pose environmental and health risks (Smichowski, 2008). Antimony is lost by emissions to water, air and land, which happen during primary production, as well as during manufacturing. The Sb capture from the air should be improved, since in 2010 global air emissions reached 1904 tons. This is caused mostly by fuel combustion, waste incineration, brake wear and metal production. Emissions from coal fired power plants, metal production plants and municipal waste incinerators can be decreased by applying air pollution system with appropriate filters, which can be then treated for Sb recovery. Situation is more complicated with emissions from vehicle break wear, since they are not localised and presently no solution is available (Dupont et al., 2016).
3.3.2
PRODUCT MANUFACTURING
Exposure to antimony metal can pose a danger for human health. People working in antimony ore and metal processing plants as well as in production of antimony chemicals or manufacturing of products are at the highest risk of exposure to Sb. The EU investigated possible health effects of exposure to antimony trioxide based on laboratory tests. The assessment identified skin irritation, toxicity to the lungs and development of tumours in the lungs from inhalation exposure. However, the use of effective working safety practices and proper equipment minimise the exposure. Monitoring of workers in antimony trioxide production plant on a long term has not identified negative health effects. Taking into account the increasing number of application for antimony, there way is which it can get into the environment, it is advised to extend the research and monitoring of antimony effects on the environment and human health (Schwarz-Schampera, 2014). According to International Antimony Association, there is no carcinogenic risk when there is no inhalation exposure, which is the case in modern, controlled workplaces using protective equipment (International Antimony Association (VZW), 2017).
3.3.3
USAGE
Antimony is considered as potentially toxic metal at very low concentrations and doesn’t have known biological functions. According to International Agency for Research on Cancer there is evidence that antimony trioxide is carcinogenic in experimental animals. However, the German Research Community and U.S. Environmental Protection Agency have not assessed Sb as carcinogenic, yet they have classified it as a pollutant (Smichowski, 2008).
3.3.4
END OF LIFE RECYCLING
The typical concentration of antimony in flame retardants in e-waste reaches 1700 mg/kg, while annual global emission of Sb in e-waste is estimated as 34000 tons, assuming global waste production of 20 million tons per year (UNEP, 2013). Environmental aspect of metal recycling is related with inappropriate treatment of collected end of life scrap. Only one third of waste electronic equipment is reported as officially treated according to EU Directive. The rest of gathered unreported electronic waste is presumed either to be treated within the EU without appropriate environmental caution or transported illegally outside of Europe, where EU environmental and health standards are not met. There is an economic incentive for shipping waste to developing countries, where informal recycling channels often use manual recycling that cause health risks for employees (UNEP, 2013).
Presence of antimony in residues from municipal waste incineration can cause risks of uncontrolled release of toxic Sb to the environment. Therefore, it is crucial to implement treatment of incineration residues (Dupont et al., 2016). It is possible to recover antimony from plastics containing flame retardant. However, the amount of Sb in those materials is highly dependent on the type of plastic and its application. Efficient recovery of Sb from those sources would require applying proper sorting and screening technologies to select particles with high Sb content, which also increase recovery costs. Those methods are for instance X-ray fluorescence spectroscopy or X-ray transparency.
3.4
SUMMARY
Antimony is a valuable metal that is mostly used in flame retardants and lead-acid batteries as hardener. It is also present in lead alloys, in plastics as catalysts and stabilisers and as decolourizing agent in glass for electronics. One of the aspects of circular economy, that is applicable also to other critical metals, is better products design. The objective is to use less resources and lower material complexity. Concepts that were created to support it are design for recycling and design for sustainability. Another aspect of circular economy is recycling. Presently, the main obstacle for recycling to take place is the lack of economic incentives. With increasing stocks of metals in many different products, their successful recovery depends strongly on the collection rate of products bearing them. Apart from end of life products, industrial processes generate substantial amounts of waste, which can be a source of valuable metals. Residues from zinc primary production are potentially sources of valuable metals, like antimony but also silver, cobalt, germanium or indium. There are also environmental concerns that need to be considered. Primary and secondary production include multiple processes that are generating emissions to the atmosphere and thereby can cause environmental issues. Antimony is lost by emissions to water, air and land, which happen during primary production, as well as during product manufacturing. According to the performed research, there is no carcinogenic risk when there is no inhalation exposure to antimony, it is however classified as pollutant.
3.5
REFERENCES
Cao, H., Chen, J., Yuan, H., & Zheng, G. (2010). Preparation of pure SbCl 3 from lead anode slime bearing high antimony and low silver. Transactions of Nonferrous Metals Society of China, 20(12), 2397–2403. https://doi.org/10.1016/S1003-6326(10)60661-9
Carlin, J. F. (2000). Antimony Recycling in the United States in 2000. U.S. Geological Survey. Retrieved from https://pubs.usgs.gov/circ/c1196q/c1196q.pdf
Dupont, D., Arnout, S., Tom, P., Koen, J., & Jones, P. T. (2016). Antimony Recovery from End-of-Life Products and Industrial Process Residues : A Critical Review. Journal of Sustainable Metallurgy, 2(1), 79–103. https://doi.org/10.1007/s40831-016-0043-y
European Commission. (2011). Circular Economy. Closing the loop. https://doi.org/10.1145/948449.948453 European Commission. (2017). Study on the review of the list of critical raw materials. Critical Raw Materials
Factsheets. Luxembourg: Publications Office of the European Union. https://doi.org/10.2873/398823
Graedel, T. E., Allwood, J., Birat, J., Hagel, C., Reck, B. K., & Sibley, S. F. (2011). What Do We Know About Metal Recycling Rates?, 15(3), 355–366. https://doi.org/10.1111/j.1530-9290.2011.00342.x
International Antimony Association (VZW). (2017). i2a’s assessment of NTP’s long-term carcinogenicity studies
on antimony trioxide (ATO). Brussels. Retrieved from
http://www.antimony.com/files/cms1/publications2016/i2a-ntp-study-assessment-final-170130.pdf Reuter, M. A., Matusewicz, R. W., & van Schaik, A. (2015). Lead, zinc and their minor elements: Enablers of a
circular economy. World of Metallurgy - ERZMETALL, 68(3), 134–148. Retrieved from
http://www.scopus.com/inward/record.url?eid=2-s2.0-84931832896&partnerID=40&md5=51610431c1edba266b32334c182bb604
Schwarz-Schampera, U. (2014). Antimony. In G. Gunn (Ed.), Critical Metals Handbook (I, pp. 70–98). John Wiley & Sons, Ltd.
Smichowski, P. (2008). Antimony in the environment as a global pollutant: A review on analytical methodologies
for its determination in atmospheric aerosols. Talanta, 75(1), 2–14.
https://doi.org/10.1016/j.talanta.2007.11.005
UNEP. (2013). Metal Recycling: Opportunities, Limits, Infrastructure. A Report of the Working Group on the Global Metal Flows to the International Resource Panel. Reuter, M. A.; Hudson, C.; van Schaik, A.; Heiskanen, K.; Meskers, C.; Hagelüken, C.
4
BARYTE
4.1
INTRODUCTION
Baryte or barite (BaSO4) consists of the barium sulfate phase and also an individual mineral group which
comprises also celestine, anglesite and anhydrite. Baryte is generally white or colorless, and is the main source of barium. Baryte and celestine in nature usually form a solid solution (Ba,Sr)SO4. Baryte occurs in a variety of
depositional environments, and is deposited through a large number of processes including biogenic, hydrothermal, and evaporation, among others. Baryte commonly occurs in lead-zinc veins in limestones, in hot spring deposits, while is also frequently found in iron ores [1].
Baryte is included in recent (2017) European Commission list of Critical Raw Materials (CRMs) among 26 more materials taking into account its high supply-risk and a high economic importance [2]. Baryte deposits are indeed limited in EU member countries (minor deposits still exist in Germany, Romania and Greece). Major deposits of the mineral occur in Brazil, Nigeria, Canada, Chile, China, India, Pakistan, Guatemala, Iran, Mexico, Morocco, Peru, Turkey, South Africa and US [3]. Small vein type barite deposits occur throughout the world, but very few are exploitable. Large vein type deposits were mainly worked before 1980s and there for the discovery of new occurrences is crucial. World baryte production for 2016 was 7.3 million tonnes. The major baryte producer countries are as follows (in thousand tons according to the “Barytes Association”): China (3,100), India (1,300), Morocco (550), United States (430), Turkey (240), Russia (210), Mexico (200), Iran (200), Kazakhstan (190) and Thailand (160).
About the 69–77% of globally produced baryte is used as a weighting agent for drilling fluids in oil and gas exploration to suppress high formation pressures and prevent blowouts. The amount of required baryte increases as a percentage of the total mud mix in relation to hole’ depth. An additional benefit of baryte is that it is non-magnetic and thus does not interfere with magnetic measurements taken in the borehole, either during logging-while-drilling or in separate drill hole logging. The baryte material used for oil drilling should have a granulometry -75 μm. The mineral is also used in added-value applications which include filler in paint and plastics, sound reduction in engine compartments, coat of automobile finishes for smoothness and corrosion resistance, friction products for automobiles and trucks, radiation-shielding cement, glass ceramics and medical applications. Furthermore, it is also used for the synthesis of barium carbonate which is a component of LED glass for television and computer screens (in cathode ray tubes) [4,5].
Baryte is also the main primary resource of barium, an alkaline earth metal which presents a similar chemical properties to magnesium, calcium, and strontium (such as medium specific weight and good electrical conductivity). Elemental barium is used for the construction of bearing alloys, lead–tin soldering alloys – to increase the creep resistance, alloy with nickel for spark plugs, additive to steel and cast iron as an inoculant, alloys with calcium, manganese, silicon, and aluminium as high-grade steel deoxidizers [4,5].
4.2
ENVIRONMENTAL ISSUES AND CIRCULAR ECONOMY ASPECTS
4.2.1
PRODUCTION
4.2.1.1
BARITE CONCENTRATE BENEFICIATION
Barite occurrences are commonly associated with fluorite (CaF2) concentrations while in most of cases contains
a variety of impurities such as a silicates, calcite, and iron as. Several processes have been developed for the beneficiation of barite concentrate prior to its use as a drilling mud. The most widely used process for barite beneficiation and enrichment consists of a combination of gravity separation and flotation techniques (Figure 1). Using this flow sheet, a chemical grade and drilling mud grade barite concentrate are produced. Flotation, which is more efficient in case of fine sized barite concentrate, can be either reverse or direct. Reverse flotation generally involves removals of base metals sulphides or pyrite leaving a concentrated barite in the tailing, which is recovered using flotation. Direct flotation of barite is performed from the ores that contain fluorspar, silicates, and Rare Earth Oxides (REO) [6]. Various agents are used at the flotation processing in relation to specific impurities. Sodium silicate is an important reagent acting as a dispersant and silicate depressant. Aluminum depresses calcite while citric acid is a fluorspar depressant and is used during barite flotation from the ores that contain fluorspar.
Physical separation processes for barite beneficiation have been used in the past. Since the early 1960s, a number of operating plants used a combination of gravity concentration and magnetic separation (Figure 2). The concentrate after the separation is submitted to acid leaching aiming to the removal of the remaining iron content.
Figure 2. Beneficiation of barite concentrate via magnetic separation method [6].
After beneficiation, the barite concentrate is classified in relation to specific applications. The barite market is divided into three main product grades as (1) drilling mud, (2) chemical grade, and (3) filler grade. The typical specifications of these products is shown in Table 1.
Recently, specific attention is given to the environmental impact of baryte when used as a weighting agent to drilling muds to counteract pressure in the geologic formations being drilled. It was found out that barite muds contain elevated (compared to marine sediments) concentrations of several metals. Some of these metals are bioavailable, may harm the local marine ecosystem [7]. An impact indictor can be considered the bioavailable fraction of metals that are dissolved from the nearly insoluble, solid barite into seawater or sediment porewater. Barite–seawater and barite–porewater distribution coefficients (Kd) have been calculated for determining the predicted bioavailable fraction of metals from drilling mud barite in the water column and sediments, respectively. Values for Kd barite–seawater and Kd barite–porewater were calculated for barium, cadmium, chromium, copper, mercury, lead, and zinc in different grades of barite. It was estimated that mercury, copper and lead are the metals with the higher distribution coefficients.
4.2.2
USAGE
Barite concentrate is widely used as a weighting agent in oil drilling muds. These high-density muds (Figure 3) are pumped down the drill stem, exit through the cutting bit and return to the surface between the drill stem and the wall of the well. The main functions of drilling barite rich mud include providing hydrostatic pressure to prevent formation fluids from entering into the well bore, keeping the drill bit clean during the drilling process and suspending the drill cuttings while drilling is paused and when the drilling assembly is removed from the hole. The drilling mud is also used to avoid formation damage and to limit corrosion. The advantages for barite’s use in this application over other materials are: its chemical neutrality, low magnetic succecibility and environmentally acceptable characteristics. Finally, it is far less abrasive than other materials and does little damage to drilling equipment.
4.2.3
END OF LIFE
Burial is the most common practice that used for the disposing of baryte-bases drilling mud wastes. Commonly, the solids are buried in a pit used for collection and temporary storage of waste mud and cuttings after the liquid is allowed to evaporate. Pit burial is a low-tech method that does not require wastes to be transported away from the well site, and, therefore, is widely used by many operators. On the other hand, burial doesn’t consist an appropriate method in case mud wastes that contain high concentrations of oil, salt, biologically available metals, industrial chemicals, and other materials with harmful components that could migrate from the pit and contaminate usable water resources. Secure landfills are specially designed land structures which employ protective measures against off-site migration of contained chemical waste via leaching or vaporization using a synthetic landfill liner [9].
Incineration is an alternative waste management choice in case of barite mud which is frequently contaminated with oil amounts. Incineration is one of the best thermal treatment disposal options because thermally treated wastes are decomposed to less hazardous by-products. Controlled incinerators operate at sufficient temperatures for complete thermal decomposition of hazardous wastes. Non-hazardous and hazardous solids, liquids, and gases can be incinerated. However, incineration of heavy metals such as lead, mercury or cadmium, frequently contained in barite, consist a parameter that should be taken into account [9].
The use of barite mud wastes, after their drying, as an aggregate for roads construction should also be examined.
4.3
SUMMARY
Baryte (Barium Sulphate) is a chemically inert heavy mineral having a specific gravity of about 4.5 g/cm3 and its
principal use is in the manufacture of oil well drilling fluids. In practice, the material used in drilling fluids has a specific gravity that ranged between 4.10 and 4.25 g/cm3. The barite market is significantly high in oil-producer
countries. For example, in US more than the 97% of 2.4 million tons of barite concentrate are consumed by the crude oil industry. The average price of baryte used for gridding purposes is 120 Euros/ton. There is a lack of an estimation concerning the ranging of price in the future, however it is obvious that drilling activities worldwide have a significant impact on barite consumption. In recent years, petroleum production in the United States increased dramatically owing to advances in the application of horizontal drilling and hydraulic fracturing in shale and other tight resources [10]. The total global production of baryte was 7.46 million tonnes, while the certain reserves does not exceed 380 million tonnes.
A number of researches are focused on the environmental impact of baryte mud in marine environment [7,11]. The results show that baryte cannot be considered as a totally chemical inert material as, in several cases, it contains traces of several heavy metals (such as mercury and lead) that can be released in the marine environment at the drilling process. The disposing practice of baryte wastes is not well defined. The most
and low operating cost, however, on the other hand harmful components can migrate from the pit and contaminate usable water resources. Therefore, further attention should be given to the barite disposing focusing on novel practices and valorization processes.
4.4
REFERENCES
[1] J. Hanor, 2000. Barite-celestine geochemistry and environments of formation". Reviews in Mineralogy. Washington, DC: Mineralogical Society of America. 40: 193–275
[2] On the 2017 list of Critical Raw Materials for the EU, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS, European Commission, Brussels.
[3]http://barytes.org/statistics.html
[4] R. Baudis, U. Jäger, P. Riechers, H. Hermann, W. Heinz, W. Wolf, H. Uwe 2007). Barium and Barium Compounds. In Ullman, Franz. Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH
[5] M. Michael Miller, 2009. Barite, Minerals Yearbook
[6] S. M. Bulatovic, 2015. Chapter 34 – Beneficiation of Barite Ores, in : Handbook of Flotation Reagents: Chemistry, Theory and Practice, Volume 3: Flotation of Industrial Minerals, pp. 129–141.
[7] J. M. Neff, 2007. Estimation of bioavailability of metals from drilling mud barite, Integrated Environmental Assessment and Management, 4 (2), pp. 184–193.
[8] Petroleum Engineering Handbook, 2007. Volume II: Drilling Engineering. Society of Petroleum Engineers. pp. 90–95.
[9] S. I. Onwukwe, M. S. Nwakaudu, 2012. Drilling wastes generation and management approach, International Journal of Environmental Science and Development, 3 (3), pp. 252-257.
[10]https://minerals.usgs.gov/minerals/pubs/commodity/barite/mcs-2016-barit.pdf
[11] T.M. Ansari, I.L. Marr, A.M. Coats, 2001. Characterisation of mineralogical forms of barium and trace heavy metal impurities in commercial barytes by EPMA, XRD and ICP-MS, Journal of Environmental Monitoring, 3(1), pp. 133-138.
5
BERYLLIUM
5.1
INTRODUCTION
The most important applications of Beryllium in the EU are
· Electronics and telecommunication equipment: Beryllium is used as an alloying element in copper to improve its mechanical properties without impairing the electric conductivity. Copper beryllium is used in electronic and electrical connectors, battery, undersea fibre optic cables, chips (consumer electronics + telecommunications infrastructure)
· Transport and Defence:
o Automotive electronics: connectors in vehicle components (CuBe) for air-bag crash sensor and deployment systems, airbags, anti-lock brake systems and many other life safety applications, for weather forecasting satellites, undersea earthquake tsunami detection monitors, air traffic control radar, fire sprinkler systems, power steering and electronic control systems, etc.
o Other light metal vehicle components (Be used in <10 ppms): car body panels, seat frames, car steering components and wheels, etc.
o Aerospace components: landing gears, engine for aircraft, mirrors for satellites, etc. · Industrial components:
o Moulds for rubber, plastics and glass, made of Be ceramics o Metals: Bar, plate, rod, tube, and customized forms
· Energy application: copper-beryllium is used to stop the leaking during the Oil spills, non-magnetic equipment component used to improve extraction equivalent of energy applications
· Others: among others, Be in medical application is used as beryllium foil for high-resolution medical radiography, including CT scanning and mammography; Be in explosives; beryllium oxide ceramic in lasers; beryllium as components to analyse blood and in X-ray equipment, etc.
Figure 1. Most important applications of Beryllium in the EU
5.2
GAPS LIMITING CIRCULAR ECONOMY
The beryllium contained in the waste usually ends up in landfill. Beryllium is not recycled from end finished products (BeST 2018).
In the case of the pure beryllium metal components, disassembling and processing old scrap are economically viable processes only for large volumes of materials with high beryllium content, such as military aircraft parts and products used in the aerospace industry. However, pure beryllium metal components used in technological applications have extremely long lifetimes, and therefore return to the recycle stream very slowly. Some, because of applications in space, or because of their sensitive military nature, do not return at all. When pure beryllium components do finally return, they can be easily recycled.
Much of the beryllium metal is contained in nuclear reactors and nuclear weapons, which are difficult to recycle and may have been contaminated. These applications are rarely dismantled, and the beryllium may have been lost during testing (Cunningham 2004)
Electronic and telecommunica tion equipment 40 % Automotive electronics 16 % Automotive components 16 % Aerospace components 10 % Energy application 8 % Moulds 3 % Metal 3 % Others 4 %
In the case of the beryllium alloys components, the Beryllium alloys are lost to the beryllium industry because they are recycled with the host metal or are lost to slag during smelting. For example, the recovery of beryllium metal from copper beryllium alloys that are included in components of post-consumer scrap (like electronics) is difficult because of the small size of the components, difficulty of separation, overall low beryllium content per device and the low beryllium content in the copper beryllium alloy (average 1.25 % beryllium). Therefore, most of the scrap is recycled for its copper value
However, beryllium can be recovered from new scrap. The “new” Beryllium scrap is generated and recovered at various stages of production. Scrap generated during the manufacture of beryllium metals and alloys, and during the fabrication of beryllium products. The European industry generates a lot of “new scrap” (around the half of the beryllium input), during this manufacture step, which is totally sent back to producers outside Europe for reprocessing (European Commission 2017).
Sometimes, regulatory restrictions on the use of certain metals may hamper the development of markets or threaten their viability. The following regulatory restrictions could be a reason that the beryllium has not received more attention to increase its recycling percentage:
- REACH. The threat of being included in the Candidate List of substances of very high concern for Authorisation could be a gap. In 2014, was included in the PACT (Public Activities Coordination Tool) Beryllium has already been subjected to an RMO-Analysis and the outcome of the assessment has been that it is “Appropriate to initiate regulatory risk management action”.
- Occupational Exposure Limit (OEL). During the Risk Management Option analysis (RMOA) one of the actions defined was the “Setting of an OEL” The Setting of an OEL by the Scientific Committee on Occupational Exposure Limits (SCOEL) has set as a necessary step forwards for the regulation of beryllium. Such an OEL may serve as a basis for further regulatory measures. This regulatory option indicates the high potential for risk reduction capacity and equivalent high health benefits for the workers. On the other hand, additional costs for the measures for exposure reduction may incur e.g. plants with encapsulated equipment. However, considering the investment for the continuous improvement, the additional costs would be proportional to the benefits arising from exposure reduction. (Source: RMOA CONCLUSION DOCUMENT )
Even when a RMOA can conclude that regulatory risk management at EU level is required for a substance or that no regulatory action is required at EU level, the risk exist.
Although nowadays the Beryllium is not recycled from end finished products (BeST, 2016b), (the end of life recycling input rate is set to 0% ) the market for Beryllium is expected to growth over the coming decades. In the STOA Report (2017) “Towards a circular economy waste management in the EU” examines the role of the waste management in the context of a circular economy transition. A preliminary analysis on the assessment of the opportunities for material recirculation is reported in the study, shown in the next figure. The figure plots the import dependency against the recycling rate of 28 CRMs. The materials in the top left quadrant are high
Figure 2. Assessment of the opportunities for material recirculation for CRMs (Source: STOA project 'Towards a circular economy – Waste management in the EU)
In the STOA Report, grouped these materials studied in the figure into four categories, Batteries (1), electronic and electrical products (2), other manufactured products including alloys, catalytic convertors and glass, (3) and industrial processes and construction (4). The study identified the Beryllium in this third group as high potential.
Figure 3. CRMs grouped by main application. Yellow shaded materials are those identified above as ‘high potential’ (Source: STOA project 'Towards a circular economy – Waste management in the EU)
5.3
ASPECTS SUPPORTING CIRCULAR ECONOMY
One of the key challenges for a circular economy policy framework will be its integration with the existing waste management. One example or instrument is the setting of Directives and regulations for individual waste streams. (i.e ELV Directive, Batteries). Waste specific directive benefit the Circularity of some CRMs, as some of the CRM with the higher “End of life recycling input rate” belong to an end of life product with a specific waste management directive.
Among others, one regulatory challenge that need to be addressed in order to develop well-functioning markets for a circular economy is the REACH regulation. A study carried out by the Center for European Policy Studies (CEPS 2018) summarizes several challenges that need to be resolved in the transition for a circular economy. One of these challenges defined are related to substances of concern and remanufacturing. The report states that “EU legislation on substances of concern aims to protect human health and the environment. A shift towards circularity would require addressing challenges while ensuring safety. The challenges relate to difficulties in remanufacturing products, uncertainty about the substances included in products and a lack of predictability for businesses regarding future restricted substances”. Given these uncertainties, investments from private sector into achieving higher circularity performances might be hindered for some specific materials.
The principle challenges summarized in this regard are
1. A difficulty with regard to innovation and competitiveness activities, especially SMEs, because they may direct their R & D work to comply with the legislation on chemical substances of the EU but they can not know the additional costs on the compliance with it.
2. Businesses may lack predictability regarding the substances that may be restricted in the future from updates in EU chemicals legislation. This in turn can cause difficulties for companies planning to use remanufactured products or product parts
3. Directive2011/65/EU on the restriction of hazardous substances (RoHS) in electrical and electronic equipment is another key piece of legislation for the protection of human health and the environment that also entails some challenges.
4. A further challenge relates to the access to information on the presence of hazardous substances in products and recovered materials. A report by Bernard & Buonsante (2017) assessing different case studies of products concluded that the current legal framework often fails to ensure the availability of information about the presence of substances in products and waste streams. This issue of uncertainty about the substances included in products may hinder the work of businesses that would like to remanufacture products or use recovered materials in order to produce new products.
5.4
REFERENCES
BeST - Beryllium Science and Technology Association http://beryllium.eu/about-beryllium/facts-and-figures/ European commission (2017). Study on the review of the list of critical raw materials. Critical raw materials factsheets
The Public Activities Coordination Tool (PACT) List 2014.
https://echa.europa.eu/es/pact?p_p_id=viewsubstances_WAR_echarevsubstanceportlet&p_p_lifecycle=0&p_ p_state=normal&p_p_mode=view&p_p_col_id=column-1&p_p_col_pos=1&p_p_col_count=2&_viewsubstances_WAR_echarevsubstanceportlet_delta=50&_viewsubst ances_WAR_echarevsubstanceportlet_keywords=&_viewsubstances_WAR_echarevsubstanceportlet_advance dSearch=false&_viewsubstances_WAR_echarevsubstanceportlet_andOperator=true&_viewsubstances_WAR_e charevsubstanceportlet_orderByCol=staticField_-104&_viewsubstances_WAR_echarevsubstanceportlet_orderByType=asc&_viewsubstances_WAR_echarevsubs tanceportlet_resetCur=false&_viewsubstances_WAR_echarevsubstanceportlet_cur=4
Beryllium details of the RMOA and hazard assessment activities. https://echa.europa.eu/es/pact/-/substance-rev/1979/del/50/col/staticField_-104/type/asc/pre/4/view
Beryllium Risk Management Option Analysis Conclusion Document https://echa.europa.eu/documents/10162/c482868d-14c2-e92a-eaef-458125e3902b
Scientific Foresight Unit (STOA) within the Directorate-General for Parliamentary Research Services (DG EPRS) of the European Parliament. 2017. STOA project 'Towards a circular economy – Waste management in the EU. Oakdene Hollins (UK).
The Centre for European Policy Studies (CEPS). 2018. The Role of Business in the Circular Economy. Markets, Processes and Enabling Policies.
6
BISMUTH
6.1
INTRODUCTION
Bismuth is a chemical element with the symbol Bi and atomic number of 83. It is a pentavalent post-transitional metal and one of the pnictogens, very chemically similar to lighter homologues: arsenic and antimony.
In earth crust bismuths is twice as aboundant as gold and the most important ores of bismuth are bismuthinite and bismite. Native bismuth is known from Australia, Bolivia and China.
Fig. 1 Bismuth Production Market Share (InV 2014).
In China and Vietnam, bismuth is a byproduct or coproduct of tungsten and other metal ore processing. It is also a by-product of several ore-dressing operations, especially from high-grade scheelite and wolframite ores. It is in general recovered by processing lead electrorefining slimes, Kroll-Betterton dross, and other process residues which contain bismuth where almost all the time chlorine is used in order to achieve virgin material (KRU 2003). Bismuth is currently recycled to a very low percent, about 5%, from EoL products.
Bismuth is used in chemicals used in cosmetic industry, industrial laboratory and pharmaceutical applications. Also, it is used in manufacturing of ceramic glazes, crystalware and pearlescent pigments.
Bismuth is considered to be an environmentally friendly substitute for lead in plumbing and many other applications, including fishing weights, hunting ammunition, lubrication greases and soldering alloys.
6.2
GAPS LIMITING CIRCULAR ECONOMY
According to UMICORE, bismuth is difficult to recycle due to it’s ”dissipative” applications (UMC 2018), such as pigments and pharmaceuticals. It is however recovered from the production of copper and lead (FUN 1992). AURUBIS is recycling copper (AUR 2018), where bismuth gets separated together with other metals.By-elements still existing during copper production, such as lead, bismuth, antimony and tellurium, are separated in the connected lead refinery and sold as lead bullion, lead-bismuth alloy, antimony concentrates and tellurium concentrates, Figure 2.
6.3
SUMMARY
Generally bismuth production is highly dependent on the production of the main metals of which the by-product bismuth is. Due to it’s rather benign properties, no special environmental harms are posed by bismuth itself, however it can be seriously affected by the main metals extraction methods, which are sometimes far away from environmentally friendly procedures.
The recycling of bismuth is a secondary process as well, no dedicated process tailored for bismuth exists currently in use.
As UMICORE highlights, the dispersive use of bismuth into other materials makes it difficult to concentrate prior to eventual recycling, thus the price of such a process would be very high.
6.4
REFERENCES
InvestorIntel – (2014) Bismuth – the X-Factor in the Chinmese Dominance Challenge, https://investorintel.com/sectors/technology-metals/technology-metals-intel/bismuth-chinese-grip/, retrieved May 2018
Funsho K. Ojebuoboh, (1992), Bismuth – Production, properties and applications, JOM, Vol. 44, Issue 4, P. 46-49 J. Kruger, P. Winkler, E. Luderiz, Manfred Luck, H. U. Wolf, (2003) – Bismuth, bismuth alloys and bismuth compounds, https://doi.org/10.1002/14356007.a04_171
UMICORE – Bismuth –http://www.umicore.com/en/about/elements/bismuth/, retrieved May 2018
AURUBIS – Recycling technology -https://www.aurubis.com/en/products/recycling/technology, retrieved May 2018.
7
BORATES
7.1
INTRODUCTION
The global mine production is about 1 million tonnes of borates. The EU consumption is estimated at approximately 285,000 tonnes (borate equivalent), which represents around 15% of world consumption (European commission 2017)
EU end uses of borates area shown in next figure. About half of all consumption globally of borates is used as an additive in glass. The next leading use is for frits and ceramics in the Ceramic Industries. The third use for boron compounds is as fertilizers in agriculture.
Figure 3. EU end uses of Borates. (Source: EU commission)
7.2
GAPS LIMITING CIRCULAR ECONOMY
The functional recycling of boron is thus null. (USGS 2017). The principal gap is that the products containing the borates are not likely to be recycled considering these products are consumed with use:
· Fertilisers: an essential micronutrient for plant growth, crop yield and seed development. · Wood preservatives: Borates are used to treat wood to ward off insects and other pests. · Detergents: Used in laundry detergents, household and industrial cleaning products. Borates
enhance stain removal and bleaching, provide alkaline buffering, soften water and improve surfactant performance. Glass 52 % Frits and ceramics 16 % Fertilizers 14 % Wood preservatives 4 % Chemicals 8 % Metals 3 % Others 3 %
· Chemicals (excl. Fertilisers, wood preservatives and detergents): Used for chemicals such as fire retardants.
· Industrial Fluids: Used for metalworking fluids, and other fluids used in cars, antifreeze, braking fluid etc.
· Metals: Used as an additive for steel and other ferrous metals as its presence ensures higher strength at a lower weight
And the Borosilicate glass and ceramic cannot be recycled with normal glass because these materials have a higher heat resistance and therefore higher melting point compared to conventional glass. The presence of this kind of glass during recycling causes defects in the recycled glass.
Secondary materials result mostly from non-functional recycling. Borosilicate glass is currently not separated from boron-free container and flat glass. It means that boron in waste borosilicate glass is likely to end up in the manufacture of new glass containers or glass wool and it does not replace primary boron in the new production of borosilicate glass. Moreover, waste from ceramics is mostly used as a construction material. (Deloitte, European commission 2017)
In the next table it is shown the EU stock of boron in use (180 kt), the annual amount of boron in end of life products collected and the amount of the amount of boron recycled.
Table 1 - Based on data of the Bio Intelligence Service Report, 2015
The EU stock of boron in use(tons)
The annual amount of boron in end of life products collected (tons)
The annual amount of boron from non-functional
recycling. (tons)
Glass 46.000 45.000 21.000
Frits and ceramics 98.000 13.000 10.000
Fertilizers 35.000 < 1.000
--Others 1.000 7.000 3.000
Total 180.000 About 66.000 34.000
The stock reflects the lifespan of particular finished products, which was the longest for frits and ceramics. More than half of boron in the collected products at end of life is sent for non-functional recycling. The annual amount of products heading for disposal is about 30 kt in boron content
Although nowadays the borates are not recycled from end finished products (BeST, 2016b), (the end of life functional recycling input rate is almost 0%), the STOA Report (2017) “Towards a circular economy waste management in the EU” identifies as a high potential material. This report assesses the role of the waste management in the context of a circular economy transition. A preliminary analysis on the assessment of the opportunities for material recirculation is reported in the study, shown in the next figure. The figure plots the
import dependency against the recycling rate of 28 CRMs. The materials in the top left quadrant are high potential materials, where it is appeared Borates.
Figure 4. Assessment of the opportunities for material recirculation for CRMs (Source: STOA project 'Towards a circular economy – Waste management in the EU)
In the STOA Report, grouped these materials studied in the figure into four categories, Batteries (1), electronic and electrical products (2), other manufactured products including alloys, catalytic convertors and glass, (3) and industrial processes and construction (4). The study identified the Borates in this third group as high potential.
Figure 5. CRMs grouped by main application. Yellow shaded materials are those identified above as ‘high potential’ (Source: STOA project 'Towards a circular economy – Waste management in the EU)
Several commercial forms of borates as sodium perborate, Perboric acid, Sodium peroxometaborate, Lead bis(tetrafluoroborate), Diboron trioxide, Boric acid, Disodium tetraborate, Tetraboron disodium heptaoxide
(hydrate) have been identified as Substances of Very High Concern (SVHC) under REACH legislation and were added to the candidate list (ECHA 2018) These compounds have also been classified as toxic for reproduction.
7.3
ASPECTS SUPPORTING CIRCULAR ECONOMY
The non-functional recycling is quite high in some of the end of life products. As it is shown in the table 1, the non-functional recycling of the ceramics reach almost a 75% of the amount collected. The “mixtures of concrete, bricks, tiles and ceramics» are identified in the list of C&D Waste classification (code 17 01 07) in the EU Construction & Demolition Waste Management Protocol (https://ec.europa.eu/growth/content/eu-construction-and-demolition-waste-protocol-0_en.
Some measures in the management of Construction &Demolition waste could have influenced, as some Proper regulation of C&D waste management, National waste plans, Landfill restrictions or bans to landfill disposal, R&D support in new construction materials.
7.4
REFERENCES
European commission (2017). Study on the review of the list of critical raw materials. critical raw materials factsheets.
USGS (2017) Minerals Yearbook, Boron.
BIO by Deloitte (2015) Study on Data for a Raw Material System Analysis: Roadmap and Test of the Fully Operational MSA for Raw Materials. Prepared for the European Commission, DG GROW
Scientific Foresight Unit (STOA) within the Directorate-General for Parliamentary Research Services (DG EPRS) of the European Parliament. 2017. STOA project 'Towards a circular economy – Waste management in the EU. Oakdene Hollins (UK).
ECHA. http://echa.europa.eu . Candidate List of substances of very high concern for Authorisation https://echa.europa.eu/candidate-list-table
8
COBALT
8.1
INTRODUCTION
Cobalt is used in a wide range of end products, either as cobalt-bearing compounds or cobalt metal. Cobalt-containing compounds find use especially in battery applications (cathode material in Li-ion batteries, anode material in Ni-MH batteries), but also in as pigments and other applications of ceramic materials (Hamut, 2017), (Ogura & Kolhe, 2017), (Llusar et al., 2001), (Delorme et al., 2017). Metallic cobalt is included in superalloys, particularly Co-based superalloys, wear-resistant cobalt-base alloys, known as Stellites, and even in biocompatible alloys of Co-Cr-Mo (Campbell, 2008).
The form in which cobalt is included in the end product, i.e., compound or bulk metal, inherently influences the circular economy aspects. Much work has been put on finding technologies to recycle and recover cobalt from battery components, primarily from cathodes of lithium ion batteries. In them, cobalt exists as lithium cobalt oxide, LiCoO2, or its invariants lithium nickel cobalt aluminium oxide or lithium nickel manganese cobalt oxide. In
general, the recovery of cobalt from the pretreated battery waste may be achieved by pyrometallurgical or hydrometallurgical routes, i.e., by smelting or leaching. Much of the work in this area has concentrated on leaching combined with a reductive treatment of the dissolved cobalt in order to optimise the conditions for the maximum yield, e.g., (Meng, Zhang, & Dong, 2018), (Peng, Hamuyuni, Wilson, & Lundström, 2018), (Meng, Zhang, & Dong, 2017), (Albler, Bica, Foreman, Holgersson, & Tyumentsev, 2018), (Torkaman, Asadollahzadeh, Torab-Mostaedi, & Ghanadi Maragheh, 2017), (Rodrigues & Mansur, 2010), (Wang et al., 2017), (Takacova, Havlik, Kukurugya, & Orac, 2016). A proof-of-concept has also been received for a pyrometallurgical route to recover cobalt (Georgi-Maschler, Friedrich, Weyhe, Heegn, & Rutz, 2012). In addition to these, some successful attempts to recover the electrode material, LiCoO2, through solid-state synthesis have been reported (Pegoretti, Dixini,
Smecellato, Biaggio, & Freitas, 2017), (Sita, da Silva, da Silva, & Scarminio, 2017).
In 1998, superalloys covered 44% of the cobalt use in USA (Shedd, 1998), with aerospace and power generation being the main consumer sectors (Srivastava, Kim, Lee, Jha, & Kim, 2014). Despite the emerge of battery revolution since then, it is clear that superalloys are an important category of use for the cobalt (Ferron, 2016). In the case of cobalt-base alloys, recycling technologies exist already yet there are several challenges to overcome. In alloy applications, the recycling of the material can easiest be done at the source, i.e., where an alloy is cast or machined. These are typically very localised individual spots, which makes the collection of scrap for recycling very easy. The most convenient way to recycle cobalt is to re-melt the scrap directly provided no harmful elements (polishing grit, cutting oils,…) have been added. (Ferron, 2016) Otherwise, the main technologies to recycle superalloy scrap and even cobalt catalysts are pyrometallurgy, hydrometallurgy and their combinations, similarly to the case of batteries, and with recognized issues of environmental hazardousness and energy intensiveness. The recycling of superalloys in general is not straightforward as typical superalloys contain more than 20 alloying elements and consideration in recycling of every single element included in the composition is very demanding. For example, in 1998 in USA, i.e., before the boom of battery technologies, the
recycling efficiency of cobalt scrap was 68% (Shedd, 1998). Here, the cobalt scrap covered superalloy parts, cemented carbide parts, magnets, spent catalysts and other metal products, but it was clearly emphasized that some of the recycled scrap underwent downgrading, i.e., dilution to the level where its properties are not fully utilized (alloying element in e.g., steel). Furthermore, one issue that directly contributes to the recycling rate is the amount of produced scrap. Indeed, it is acknowledged that the superalloy industry releases an extremely large amount of scrap: components may have a final product yield of less than 10% due to machining and forging (Srivastava et al., 2014).
For Stellite, i.e., cemented carbide or hard metal structures, the recycling processes fall into direct and indirect ones. Direct methods include cold stream process, like gas atomization but conducted at lower temperatures, and zinc melt process, in which the material is immersed in molten zinc bath to react selectively with cobalt and to introduce a porous structure, from which the zinc can be heated away and Co and WC powders separated (Katiyar, Randhawa, Hait, Jana, & Singh, 2014), (Kim, Seo, & Son, 2014), (Hämäläinen & Isomäki, 2005). The indirect recycling methods involve sequential steps of dry and wet processes, such as chlorination, oxidation-alkaline leaching and oxidation-reduction, to enable selective recovery of the elements included in the material (Katiyar et al., 2014), (Kim et al., 2014). During the recent years, finding the optimal combination of processes and process parameters has gained a lot of research effort. (Kim et al., 2014), (J. C. Lee et al., 2011), (Kücher, Luidold, Czettl, & Storf, 2018), (Xi, Xiao, Nie, Zhang, & Ma, 2017), yet some of the processes still give very low cobalt yield rates, e.g., (J. Lee, Kim, & Kim, 2017).
Recent figures reveal that end-of-life recycling input rate (EOL-RIR) for cobalt is 35%. It is third highest among the critical raw materials (CRM) after vanadium (44%) and tungsten (42%). However, this is mainly because a wide use of cobalt in battery applications and the existing waste legislation that requires the collection of end-of-life batteries. However, still much of the waste cobalt ends up in, e.g., landfill. (Mathieux et al., 2017)
Figure 1. Simplified Sankey diagram for cobalt in EU expressed in t/year for the year 2012. (Mathieux et al., 2017)
8.2
GAPS LIMITING CIRCULAR ECONOMY
As demonstrated above, the technologies that are used in cobalt recycling are partly coherent, particularly in the recovery of cobalt from battery electrodes and superalloy scrap, but when the hard tungsten carbides are included, the processes and technologies become more complex. The technologies thus exist, although with variable yield rate and economic feasibility. The gaps that limit circular economy of cobalt are, however, very application linked and will be treated below one by one.
Concerning the recycling of batteries, the main goals are the separation and recovery of battery components and removal of waste from the environment. The following problems have been identified in the battery recycling:
1) The low collection rate of batteries. Limited number of battery collection points in the municipalities (although the sellers should serve for collection points, particularly in the case of consumer products) combined with an easiness of storage of old batteries in a drawer.
2) The intrinsic safety risk because of the high reactivity of batteries. If overheated or overcharged, as it may happen if stored in masses, the batteries may experience a thermal runaway or even explosion. 3) The market is in continuous evolution with the advent of many new chemistries and electrode materials.
4) Parallel use of various electrolyte types and compositions in batteries, making it challenging to develop an universally valid and economically feasible recycling process.
5) The recycling at present only covers portable batteries for consumer electronics due to limited production of batteries for, e.g., electric vehicles (EV). EV battery recycling is expected to gain importance in the years to come.
These problems then also cover cobalt included in the battery electrodes. In addition to these, the amount of cobalt (and some other valuable elements) in a battery may vary significantly, between as low as 1 % and almost 50 wt.% (Ferron, 2016), thus the recycling is not always economically viable. (Scrosati, Garche, & Sun, 2015). Figure 2 shows the steps needed to recover most of the valuable elements in the batteries, and their number well reflects the economic challenges related to recovery of cobalt and other key elements.
Figure 2. Flow sheet showing the recent advances in the recycling of elements included in batteries and the number of steps needed to recover the valuables. Many of the steps employ ionic liquids. Figure from ref. (Scrosati et al., 2015)
The European Commission has mandated a Battery and Accumulator Directive to give recycling targets. In many cases, subsidies are provided to encourage the battery recycling, usually by adding a tax on each manufactured battery. The directive also prohibits to place on the market of batteries or accumulators containing more than 0.0005 wt.% mercury or 0.002 wt.% cadmium (Ec, 2000). Concerning specifically the recycling of cobalt from the battery components, the major technical challenges are the unestablished technology, documented wide variation in recycling efficiency and the use of extreme pH values in process electrolytes, requiring careful health and safety precautions.
For metallic material, the recovery is technically much easier, and there is a traceable system for scrap collection and logistics (even internationally) as demonstrated by Shedd. However, the collection and processing of cobalt-bearing scrap depends on several factors, such as the type, quality and volume of the scrap. Alloy scrap is sorted based on the shape, colour and weight of the scrap items. Other sorting methods, such as response to a magnet, may also be employed together with chemical analyses. (Shedd, 1998) However, cobalt is a very common alloying element, meaning it exists in alloys at varying levels, and the material may contain increased amount of impurity elements from the use, thus influencing the further processing. There are also some technical challenges related to the multi-element character of the alloys. All elements cannot typically be recovered simultaneously and at equal efficiencies. For example, recycling by pyrometallurgical routes may easily cause the loss of approximately 20% in the amount of alloying elements. Overall, it is not rare that cobalt undergoes downgrading upon recycling. Furthermore, in some countries, e.g., Korea, the recycling of superalloys is exclusively done by the material supplier and related to maintenance of gas turbines in power stations. (Srivastava et al., 2014) Similarly, the recycling of cobalt from hardmetal is established technology, yet it requires several steps and may not always be economically feasible due to, e.g., energy intensivity. Some of the recycling processes also have specific purity requirements for the waste to be recovered. (Shemi, Magumise, Ndlovu, & Sacks, 2018)
Some end use of the metal does not lend itself to recycling because the cobalt is dispersed in such a way that it is very difficult to collect, e.g., pigments.
8.3
ASPECTS SUPPORTING CIRCULAR ECONOMY
In the case of cobalt, the aspects that inherently support circular economy are the established technologies for recovery. Also the understanding that cobalt reserves are finite and concentrated on some local areas serves as incentive for cobalt circularity. It is also acknowledged that the recycling of cobalt occurs at lower costs that the extraction from ores, thus this is recognized the key motivation for cobalt recycling. In battery applications, the collection of end-of-life battery waste is also required by waste legislation, thus putting pressures to cobalt recycling in this sector. (Mathieux et al., 2017)
8.4
ENVIRONMENTAL ISSUES
Cobalt has a biologically necessary role as a metal constituent of vitamin B12, but excessive exposure may induce various adverse health effects, such as neurological, cardiovascular and endocrine deficits. For example, toxis reactions have been reported in the several cases of malfunctioning metal-to-metal Co-based hip implants. It is expected that the primary toxic form of cobalt is free ionic Co2+. (Leyssens, Vinck, Van Der Straeten, Wuyts, &
Maes, 2017) This is also good to bear in mind in the cobalt recovery through hydrometallurgical routes.
8.5
SUMMARY
Cobalt is one of the critical raw materials with relatively high recycling rate, 35%. However, still some of the end-of-life cobalt ends up in, e.g., landfill. The waste legislation requires to collect battery waste, but the circular economy is still limited by a limited number of collection points, safety risks related to their storage in masses and continuous evolution of battery designs and chemistries that makes it challenging to develop universal recycling solutions. Also the cobalt contents in batteries vary, challenging the economic feasibility of recycling processes. Metallic cobalt and cobalt included in hardmetal components are recycled through established technologies, yet in the case of superalloys, the high number of alloying elements present implies that not all of them cannot be recovered. The recovery of cobalt from hardmetal requires several process steps, thus the process volumes need to be large to be economically viable. In the recycling of cobalt-base scrap, local ecosystems play an important role, although the markets are also global.
